Quiet flow retarding device



Aug. 10, 1937. w. F. PETERSON ET AL QUIET FLOW RETARDING DEVICE Filed April 20, 1956 Patented Au 10, 1937 QUIET FLOW RETARDING DEVICE Walker F. Peterson and Albert U. Walter, Baltimore, Md., assignors to Baltimore Valve Corporation, Baltimore, Md., a corporation of Maryland Application April 20, 1936, Serial No. 75,474

14 Claims.

This invention relates to improvements in devices for obtaining a quiet flow of liquids such as water, and is particularly concerned with quieting the fiow of such a liquid in passing from a zone of high pressure to one of lower pressure.

It has heretofore been the practice to form valves by casting in sand molds. In such instances the practice is to dress the seat surfaces, at which restricted passages occur in closing, by machine operations. It is also the practice in providing restricted passageways in valve structures, at points other than the valve seat, to use a machined or otherwise smooth finished surface or, where a cast surface is used, to cast such surface as smooth as possible and to tumble or otherwise treat it to obtain smoothness.

Anobject of the present invention is to provide such restricting passageways, wherever they may occur, with rough surfaces so as to reduce the noise therein and at and beyond the discharge therefrom.

In our copending applications Serial No. 737,- 842, filed July 31, 1934, and Serial No. 63,258, filed February 10, 1936, we have set out and disclosed quiet flow retarding devices which operate by limiting the thickness of a flowing sheet of water. As stated in these applications, the thickness of the sheet should be less than 0.125 inch, and preferably is of a thickness of 0.030 to 0.060 inch for devices which are to operate on average city water pressure and discharge into a tank or other receptacle which is under a low pressure, such as atmospheric pressure. It has been found that a particular roughening of the walls of the 35 passageway appears to change the character of .fiow within the passageway itselt, and also at and beyond the discharge therefrom, as is plainly evi-,

dent from the reduction in turbulence in the discharge chamber. Such roughening of the walls 40 of the passageway causes them to exert a decidedly greater retarding effect per unit of length than smooth walls with the same clear -dis-, tance therebetween, and thus to permit the use of a shorter passageway for a given wall spac- 4 ing, and a given amount of retardation. Also the thickness of the fiowing sheet of water may be materially increased, when the surfaces or walls of the passageway are roughened, without changing the quantity of flow, and thus the pos- 50 sibility of clogging of the passageway by suspended matter in the liquid is proportionately reduced. Likewise, the critical velocity at which noise occurs is increased, and the amount of noise above such critical velocity is reduced; and

55 this effect is produced by presenting such a roughened wall along the path of flow of the liquid even with types of passageways other than those described in the co-pending applications, e. g. it

is effective with passageways of circular section; however, the effectiveness of roughened surfaces 5 in passageways of other than the thin-sheet type is quite limited both with respect to the area of the passageway and the velocity ,therethrough.

Furthermore, it has been found that by the use of roughened surfacesin passageways, the 10 divergence or rate of increase of cross-section may be materially increased without causing noise. This applies to all shapes of restricting passageways.

By roughened surface throughout this speci- I5 fication and claims is meant a surface having depressions and elevations throughout, so that the surface is similar to that of ordinary sandpaper of the type known commercially as #3/0 to #3, or similar tothat resulting from cutting full 20 or partial lepth threads with adjacent threads spaced 16 t i 80 to the inch, and of either single or multiple pitch, or similarly spaced peripheral grooves and ribs; or similar to the surface of a single or double cut file with a coarseness from 25 bastard to dead smooth, or a knurled surface of like spacings. Further, it has been found that the minimum depth of the depressions between the grains, threads or ribs should not be less than 0.005 inch.

As set out in our copending applications, it is found that for a given pressure differential between the inlet and outlet of any retarding device, there is a particular critical velocity above which noise occurs. This critical velocity and the amount of noise occurring above it depend on a number of factors determined by the condition of the liquid being handled and the physical structure of the retarding device itself. Thus it will vary with the amount of absorbed or dissolved air in water and the vapor tension existing; while with respect tothe apparatus, it depends upon the abruptness in change of rate or direction of flow, the spacing of the passageway walls, the length of the restricted portions of the passageway presented for the flow, the pressure differential between the inlet' and outlet of the device, and upon the absolute back pressure at the outlet end of the device. It has been found that when the walls of the restricted passageways are roughened, the critical velocity above which noise occurs is increased or the amount of noise occurring above such critical velocityis reduced for all of the above factors. I

Illustrative forms of practicing the present invention are shown on the accompanying drawing, in which:

Figures 1 and 2 are end and side elevations of a flattened tube, with parts broken away to show the internal construction.

Figure 3 is a diametrical section view through a modified form, showing an adjustable flow retarding device embodying the present invention.

Figure 41s a diametrical sectional view through a further modified form.

Figure 5 is a fragmentary sectional view showing a preferred manner of forming the grooves in the structure of Figs. 1 and 2.

In the form shown in Figs. 1 and 2, a quiet flow retarding device is constructed by providing a length of tubing with external threads ID at its upper end and with a flattened ribbed internal surface ll. Such a device may be employed as taught in our copending application Serial No. 137,842, for employment in a toilet tank for quieting the flow of water during the refilling period. In this employment, the water from the ballcock is delivered at the upper inlet end l2 of the tube and is discharged at the lower outlet end l3 into the tank, this lower end being always submerged so that the water issuing from the tube is delivered into a larger body of water which is subjected to atmospheric pressure at its upper surface.

A preferred manner of forming the roughened surface within the flattened portion of the tube is to tap the interior of a straight cylindrical tube with threads having a pitch of from 32 to 60 threads per inch, by the use of a machine tap of the requisite diameter. The threaded structure is then crushed to provide opposite walls I4 which are flat and parallel in this illustrated form, and are spaced apart a distance of 0.040 to 0.070 inch, and thus operate in conjunction with the end portions I! which are integral therewith to deflne a thin sheet of flowing water. to impose a retarding effect to the downward movement of this water and to change the character of flow within the tube and within the discharge therefrom.

It has been found that this structu'reoperates excellently under city main pressures of water of l 35 to 125 pounds per square inch, discharging the water directly into a toilet tank of the usual type. As set out in our copending application Serial No. 737,842, the flattened or crushed tube has substantially the same perimeter at its inlet and outlet ends, but the cross-section for'water flow has been modified and reduced. The length in the direction of flow andthe breadth normal to the direction of flow of the restricted passage provided between the opposed wall portions i4 is determined by the pressure differential; but it has been found that a length of 3 to 4 inches and a breadth of about inch is effective under any normal conditions of city water pressure, and regardless of the condition of this water. The preferred spacing of the walls is from 0.030 to 0.070 inch, the latter being used for pressures of say 30 pounds: and it has been found that a spacing of 0.048 inch is satisfactory over a wide range of pressures as used in many cities.

It is preferred to utilize a sharp-bottom v thread for providing theroughened surfaces in thisparticula'r form. If the thread is cutfor the full depth in this particular form, at certain slow rates or flow a very distinct and clear note, or series of notes. like a whistle, may be produced.

1 It has been found that the'noise or whistle in this particular form can be avoided by using 9.

partial depth thread instead of a full depth thread on the inside of the tube. Thus, as shown in Figure 5, lands I6 are left between the successive threads which are out only to a fraction of their normal depth. This fraction as shown in Figure 5 is approximately of the full depth. It is found that the use of such partial threads does not materially affect the rate of flow, the critical velocity at which noise occurs, or the amount of noise above such critical velocity and that threads only 25% of their normal full depth may be used without undue loss of efficiency or effect.

In the form shown in Fig. 3. the body 20 of a regulating valve has an inlet passage 2| and a discharge passage 22, and is closed by a cover 22 having a packing 24 surrounding a stem 25. This stem is connected to a regulat-able inner member 26. The stem 25 is provided with threads so that the rotation of the stem causes the member 25 to move axially relative to the valve body 20. The external surfaces of the head 28 and the opposed wall 21 in the valve body are illustrated as being formed as cones having their apices downward and having identical apex angles. A seating washer 29 is secured to the regulatable inner member or plug 26 by a screw 29a, and serves as a stop to prevent contact of the plug with the body (which might result in mutilation of the threads) and also to assure a shut-off by engaging the valve seat 2 la on the body 2|, if desired, by moving the plug to its limit of travel. The conical surface of the head 26 is illustrated as being roughened by chasing a typical 40 pitch thread thereon. The conical surface 21 of the body is illustrated as being roughened by cutting a series of peripheral grooves without pitch. This latter is done because of manufacturing expediency. Either regular pitch threads or a series of grooves without pitch give the same results. Such grooves or threads need not be normal to the direction of flow but should be at an acute angle thereto so that the grooves will not form channels for the flow of the liquid.

In an arrangement as shown in Figure 3 in which the apex angle of the two conical surfaces is the same (that is, the "annular sheet is of uniform thickness), the increase in cross-sectional area of the annular space for water flow, is

determined by the angle of the cones and the centage increase in cross-sectional area of flow is further increased.

In this form, the spacing between the opposed roughened surfaces may be varied by moving the regulating member 26 axially by rotating the stem 25. Thus the device may be adjusted for different pressure differentials, and an optimum condition of adjustment obtained at which the device is quiet even with considerable variations in the pressure differential.

In a particular installation of this type, the axial length of the conical surface in the body was seven-eighths of an inch; the axial length of the inner member was five-eighths of an inch and its smaller diameter was 1.125 inches. The apex angle of both cones was 22 degrees. Both members were formed with endless ribs of triangular section separated by grooves of like section, with a spacing or pitch of one-fortieth of an inch. At an adjustment of about 0.020 to 0.030 vinch for the clear distance between the ribs, the device operated satisfactorily upon city water pressures of 100 pounds maintained pres-' sure, in controlling the water supply to an automatic flushing valve and thence to a toilet.

While such subustantially regular formation, by ribs or grooves or threads, has been found operative, it is feasible to provide roughened surfaces in other ways.

In the form shown in Fig. 4, a cylindrical water supply tube 30 receives a flow of water from an inlet connection 3| and discharges this water into an outlet connection 32. The tube 30 may be the supply tube leading from an automatic flushing valve, as set out in our copending application Serial No. 63,258. Within this tube 30 is supported a hollow cylindrical filler structure 33 having a closed and slightly rounded upper end, and provided with a connection member'fl joined to a spider 35 which is supported at the upper end of the tube 30.

In this form, the internal surface of the tube 30 and the external surface of the filler structure 33 are provided with suitable roughened surfaces by applying a coating of shellac and then sprinkling the surface with sand or similar particles (of fineness corresponding to that of the particles on #3/0 to #3 sandpaper), to completely cover the. coated surfaces. When the shellac varnish has set by evaporation of the solvent, the sand grains remain extending into the space between the tube 30 and the filler structure 33, while depressions exist between the, individual sand grains. Obviously, other binders than shellac may be employed for the same purpose.

The preferred spacing between the two roughened surfaces, that is, the clear spacing between the projecting sand grains thereof, is of the order of 0.020 to 0.070 inch, as this has been found to give an advantageous control with normal city water-main pressures. In a particular example, where this arrangement found satisfactory employment between an automatic flushing valve and a toilet, the outer tube 30 had an internal diameter of about 1.430 inches, and the inner member 32 had an external diameter of about 1.254 inches and a length of 2 inches. Each surface has a coating with sand so that the clear distance was about 0.048 inch. With a pressure immediately in front of the automatic flushing valve from 20 to 50 pounds, a proper rateof flow was obtained for flushing the bowl. In this case the outer tube 30 was much longer than the inner member 32 and provided a continuous roughened surface extending continuously at the passageway and along such extended part of the outer tube.

The diameters of the tube 30 and filler structure 33 are selected so that the peripheral length of the annular sheet of water will afford a sufficient volume of flow for accomplishing the purposes desired. Hence this dimension may be increased or reduced according to the quantity to be delivered per unit of time.

with satisfactory results. In such a case, the clear spacing between the walls should be slightly less than if both walls were roughened: for example, 0.035 inch is then satisfactory.

Ininstances where pressure differentials are not so great, the filler structure 33 may be omitted, correspondingly dimensioning the internal diameter, for example, inside the coating on the tube 30, that is, the clear passage space should not exceed of an inch, as greater diameters do not lead to a proper effect of the roughened surfaces on the retardation of the flow and the character of the flow and the discharge. For greater rates of flow than can be satisfied by a passageway having a diameter of of an inch, it is desirable to employ a filter structure 33 as taught in Fig. 4.

It will be noted that the present invention differs from the prior practice of providing smooth or machined surfaces in restricting passageways in that the roughness is not only retained but is accentuated and made definite over these restricted passage surfaces. The roughened surfaces are preferably made as long as possible, provided that a satisfactory volume of flow is maintained and with due regard to the space available. The length in the direction of flow should be at least ten times the clear distance between opposed Walls, for usual city water pressures: and at least five successive elevations should be presented along each thread or path of flow of water.

While several modified forms of practicing the invention have been shown on the accompanying drawing, it is obvious that the invention is not limited thereto but that 'it may be employed in any way within the scope of the appended claims.

We claim:

1. A device for retarding the flow of a liquid with substantial quietness, comprising a structure providing a passageway for the flow of the liquid therealong, at least portions of the wall of the passageway having their surfaces provided with roughening comprising successive elevations and depressions in the direction of fiow..

2. A device for retarding the flow of a liquid with substantial quietness, comprising a structure providing a passageway having an inlet and an outlet and having a roughened surface presenting successive elevations and depressions along the path of flow of the liquid through the passageway from the inlet toward the outlet.

3. A device for retarding the flow of a liquid with substantial quietness, comprising means providing a passage having opposed walls which are spaced apart a minimum distance of 0.015 inch and a maximum distance of 0.125 inch for a distance at least ten times the minimum distance between the surfaces, at least one of said walls having a roughened surface consisting of elevations and depressions spaced apart a dis- .tance from to A of an inch in the direction of flow along said surfaces.

4. A device for retarding the flow of a liquid with substantial quietness, comprising an outer member and an inner member spaced apart a elevations spaced apart a distance from 1; to

of an inch in the direction of flow along the passageway.

5. A device for retarding the flow of a liquid with substantial quietness, comprising walls 5 spaced apart a clear distance of 0.030 to 0.080 inch, said walls being substantially uniformly spaced and having alternate ribs and grooves with the ribs spaced apart a distance from g; to A of an inch in the direction of flow between said members.

6. A device for retarding the flow of a liquid with substantial quietness, comprising an outer member and an inner member spaced apart to provide a passageway with a clear distance of 0.015 to 0.125'inch between said members, one member extending downstreamward past the other with its surface extending continuously from the passageway and along the extension, at least one of said members having its surface 2 roughened at the passageway.

7. A device for retarding the flow of a liquid with substantial quietness, comprising an outer member and an inner member, said' members having opposed walls of generally conical shape and spaced apart a. clear distance of 0.015 to 0.125 inch and having a roughening thereon comprising elevations and depressions, the ele- -vatlons being spaced apart a distance from to A of an inch in the direction of flow between said members.

8. A device for retarding the flow of a liquid with substantial quietness, comprising a tubular structure having a cylindrical inlet and having opposed walls extending toward the dis- 5 charge end, the cross sectional area of the inlet being greater than the cross sectional area between said walls, said opposed walls having roughened surfaces and being uniformly spaced apart a distanceof 0.015 to 0.125 inch.

9. A device for retarding the flow of a liquid with substantial quietness, comprising a cylindrical outer member, a cylindrical inner member having a closed upstreamward end, and means for supporting said inner member in said outer member, said inner member being shorter than said outer member, said members providing between them a passageway for flow of the liquid and being substantially uniformly spaced apart throughout their circumferences and throughout 00 the length of the inner member, said members having their surfaces'roughened at said passages way and the roughening on the outer member extending downstreamward past the end of the inner member.

10. A device for retarding the flow of a liquid with substantial quietness, comprising means pro: viding a passageway having opposed walls separated a distance between 0.015 and 0.125 inch, at least one said wall having ribs and grooves extending transversely to the direction of flow of liquid through the passage, the ribs being spaced apart from to of an inch and having substantially flat land portions having a width in excess of 0.005 inch and the grooves having a depth in excess of 0.005 inch.

11. A device as in claim 10, in which the ribs and grooves comprise V-thread grooves spaced apart a distance greater than the depth of the grooves for providing said land portions.

12. A device for retarding theflow of a liquid with substantial quietness, comprising a tube having a cylindrical inlet portion and a retarding portion, the periphery of the inlet portion being substantially the same as the periphery of the retarding portion, the cross sectional area of passage in the inlet portion being greater than the cross sectional area of passage in the retarding portion, said retarding portion having its walls provided with alternate ribs and grooves spaced apart from .to of an inch, said tube being formed by providing threads in a cylindrical tube and deforming said tube at the retarding portion to reduce the cross sectional area of passage thereof. v

13. A device as in claim 12, in which the said threads are of v-type and have been cut for 25% to of full depth.

14. A device for retarding the flow of a liquid with substantial quietness, comprising a body member having a truncated conical passage therein and a valve seat at the smaller end of said passage, a plug member of conical shape substantially corresponding to the conical shape of the passageway and having at its smaller end a valve member for engaging said seat, means for moving said members axially relative to one another and for engaging said valve member with said valve seat, said passageway and plug member providing between them a passage for the flow of liquid, said valve member and seat operating as a stop to prevent contact of the peripheral surface of the plug member with the wall of the body member which provides said conical passageway, and roughening on the wall of said conical passageway and on the peripheral surface of said plug member.

WALKER F. PETERSON. ALBERT U. WALTER. 

